The taste systems of several rodent species exhibit impressive morphological and physiological alteration during a prolonged postnatal period. In hamster, remarkable postnatal changes in sodium and saccharide sensing have been described, and preliminary evidence suggests that hamster bitter sensitivity also undergoes considerable developmental alteration. Evidence suggests that changes in bitter and sweet sensing could depend upon age-regulated expression of elements of the receptor/transduction apparatuses for these stimuli. Thus, the specific aims of the proposed research are to identify the temporal and spatial expression pattern of G protein-coupled receptors for sweet (and, time permitting, bitter) stimuli in developing hamster taste system primarily using in situ hybridization and confocal microscopy. The proposed research represents an initial exploration of the molecular basis for the postnatal ontogeny of physiological sensitivity to sweet taste stimuli. More fundamentally, it would provide additional insight regarding the molecular basis for taste sensing in this important rodent model of peripheral and central gustatory structure and function. The findings from the proposed work will be valuable in constructing a mechanistic understanding of age-related changes in taste stimulus sensing mechanisms. Such developmental changes in taste function may act to shape adult dietary predilections, and thus could influence diet-related risk factors in cardiovascular, renal, metabolic, and/or neoplastic disease. Therefore, the proposed work may also provide information of significant clinical value.